Medusans - Disembodied blobs of
energy whose visage caused madness when looked upon on episode No.
62 "Is There In Truth No Beauty?" on the sci-fi series STAR
TREK/NBC/1966-69. The Medusans were an intelligent race of
creatures who sent an ambassador named Kollos to the United
Federation of Planets via the USS Enterprise.

Persons
handling the diplomat, who was encased in a heavily shielded
container, needed to wear special glasses to protect them from the
rays of light emanating from the alien's form.

Vulcan science officer, Mr. Spock
accidentally gazed upon the alien without his protective glasses
and was temporarily driven insane. Luckily, the Medusan ambassador
telepathically linked minds with Spock and brought him back to
normalcy.